Method and means for casting



Jan. 20, 1931-. v D. 'H, MELOCHE 1,789,943

METHOD AND MEANS FOR CASTING Filed Sept. 25. 1926 5 Sheets-Sheet 1INVENTOR 19M [MW fif' TTORNEY Jan. 20, 1931. p. H.MELOCHE 1,789,943

METHOD AND MEANS FOR CASTING Filed Sept. 25, 1926 3 Shnets-5heet 2 fi x.as a1 a4 as 1518' 2516 24 15 as 1a 25 2431 INVENTOR ORNEY Jan. 20, 1931.D. H. MELOCHE METHOD AND MEANS FOR CASTING Filed Sept. 25, 1926 3Sheets-Sheet 5 INVENTOR ATTORNEY Patented Jan. 20, 1931 UNITED STATESPATENT OFFICE DANIEL H. MELOCHE, orBRoNXvrLLn; new YORK,. ASSIGNOR TOAMERICAN BADI- ATOR company, on NEW YORK, N. Y., A CORPORATION OF NEWJERSEY METHOD 'AND MEANS FOR CASTING Application filed September 251926. Serial No; 137,642.

My invention relatesbroadly and generally to new and useful improvementsin methods and means for the casting of metal objects, and particularlyto casting of pistons and similar elements for use in internalcombustion engines.

In the production of cast metal pistons for internal combustion engines,it is generally recognized to be highly desirable to produce 1 a castingwhich will be of light weight, accurately cylindrical in externalcontour, hav ing a relatively thin metal line of uniform thickness, andwhich will require a minimum amount of machining to render the'castingavailable for installation. It is also desirable that such a casting beas free as possible of internal strains so that the same will not crackwhen being machined, or subjected to heat effects inservice. 7

So far as I am aware, all prior available methods employing sand moldsfor casting metal pistons have required theuse of cope and dragmoldsections containing matching sand prints to form a mold, and thelocating of a suitable core or cores in the mold, the cores being eitherpart of the sand mold in the cope or drag, or separate from the cope anddrag molds and suported in the mold by suitable means. While suchmethods have been used commercially, the use thereof has been attendedwith objectionable results, arising'mainly from core shifts, swells inthe casting, and occluded gases and internal strains in the casting, allof'which resulted in non-uniformity in metal line, contour and weight,and in imperfect castings unfit for machining, or which cracked, duetointernal stresses, resulting in a large loss. Furthermore, the priormethods have necessitated that the casting be made heavier and of a muchthicker metal line-than required in the finished or machined piston, soas to assure enough metal. in the casting so that when finished it wouldmeet the requirements of the specifications for the finished piston, sofar as dimensions were concerned.

By the known methods it has been practically impossible to castlargevnumbers of pistons whichg will be of uniform, weight,

der the castingsready formachining, such,

for example, as snagging sprues and grinding off fins, ridges or otherercrescencieson thecastingwhich were unavoidable in the old method ofmolding with cope and drag, and resulted from the diliiculty of makingall cope and drag moldsmatch accurately.

A further object is to produce castings of the character mentioned,which will be free of objectionable internal strains which result incracking during setting of the casting,

during annealing, when machined, and when in service in an internalcombustion engine.

A further object is to produce castings uniformly free of occludedgases, and therefore non-porous so as to reduce lossincidental to theoccluded gases or porosity, and which can usually only be discoveredafter the casting has been partly or wholly machined, or when itis'subjected to the stresses attending use.

A further object is to provide an apparatus which will successfullyattain the objects heretofore set forth.

The invention consists in the novel method and apparatus for carryingthe same into effect, to be more fully described hereinafter, and thenovelty of which will be particularly pointed out and distinctlyclaimed.

In the accompanying drawings I have illustrated a preferred embodimentof an apparatus constituting my invention, and wh1ch constitutes onemeans-for carrying my improvedmethod into effect. I

Figure/ 1 is a perspective View of a fiask employed in the practice ofmy invention;

Fig. 2is aperspectiveof a pattern element ll mpley d carryin t. t e inven; i

' ton casting.

Fig. 3 is a top plan view of a core support and positioning member;

Fig. 4 is a perspective view of a preferred form of core;

Fig. Eris a perspective view of a holding member for holding the coresin position in the core-supporting element shown in Fig. 3;

Fig. 6 is a longitudinal sectional view showing the elements illustratedin Figs. 1, 3, 4c and 5' assembled for the pouring of a mold, and

Figs. 7, S and 9 are detail sectional views showing the steps ofperforming the method previous to the assembly of elements shown in Fig.6.

Before proceeding with a detailed description of my invention, I wouldstate that I have shown the same as embodied in an apparatus capable ofproviding for multiple casting, so as to permit the economical and rapidproduction of a number of castings simultaneously. However, theinvention is not to be limited to multiple casting, as it contemplatesembodiment in either single or multiple casting. In carrying out myinvention in its preferred form, I employ a flask or mold 1, which ispreferably rectangular in construction and open at its top and bottom.This mold box is preferably of a depth sufficient to hold sufficientsand to form a sand mold for molding an entire pis- The top and bottomedge, faces of the mold box are preferably made to lie in exact parallelplanes in order to effect the result to be hereinafter described.Opposite walls of the flask are provided withextei sions or lugs 2,provided, respectively, with guide apertures 3, there being preferably apair of such guide apertures in each lug, said apertures being adaptedto receive guide means preferably in the form of pins carried by apattern-carrying element, and also by a core-supporting element to behereinafter described.

4 designates a pattern element, preferably consisting of a flat plate orboard, carrying on one side thereof patterns 5 of such shape or contouras to form in a green sand mold prints or cavities corresponding to theexternal configuration it is desired to impart to the casting. In thepresent embodiment each of these patterns is a true cylinder arrangedwith its longitudinal axis at right angles to the plane of the face ofthe pattern board, and symmetrically spaced thereon.

The pattern board is provided with guide means preferably in the form ofspaced pins 6 adapted to cooperate with the openings 3 in the lugs 2 toaccurately position the patterns within the flask 1 when the patternelement is applied to the open end of the flask (see Fig. 7 It will beunderstood that in the preferred form the apertures 3 in the lugs 2 onthe flask and the pins 6 on the pattern board are so located that thepattern board is reversible end for end with respect to the flask, sothat the, patterns will occupy a determined and accurate position in theflask. In forming the sand mold or print in the flask, the flask 1 isarranged on a suitable support with the lugs 2 uppermost, and thepattern board 4; is then applied to the upper open end of the flask,being guided and held in position by engagement of the pins 6 thereonwith the guide openings on the flask (see Fig. 7 It will be understoodthat the under face of the pattern board is made preferably flat, and atright angles to the longitudinal axis of the patterns, so that when thepattern board is applied in position the pat terns will project into themold-containing portion of the flask. It will be noted that thesepatterns are of such length that they terminate short of the bottom ofthe flask when in the position just described, so as to provide acasting space to form a piston.

The pattern board having been located on the fla sk as just described,the flask 1 is rolled over by any suitable agency, so that the patternboard 4 is located on the bottom of the flask with the patternsprojecting upwardly in. the latter (see Fig. 8). Mold-forming sand T'isthen placed in the flask and is rammed or packed therein about thepatterns, and then any suitable means is employed to level the sand inthe flask. The sand may be rammed, or packed by hand, or by any wellknown jolt, or squeeze mechanism. After striking of the mold a suitablebottom board 8 is applied thereto, the bottom'board and the patternboard being held to the flask by any suitable means (not shown). Themold is then rolled over to bring the pattern board uppermost, as shownin Fig. 9, and the pattern is then drawn by any suitable means toseparate it from the mold in the flask. As the result the flask containsa sand mold containing one or more cylindrical cavities or prints 9which establish the external contour of the casting to be made. It willalso be noted that each of these prints forms the external contour of acomplete cylindrical piston casting, and that the print is located with.its longitudinal axis at right angles-to the plane of the upper edge ofthe flask and the face of the body of sand in the flask. Each of theprints in the mold is then ready to receive a core adapted to cooperatewith the print 9 to form a casting, and in its'preferred embodiment mayform additional parts, for example, the gudgeon pin bosses for receivingthe pin for connecting the finished piston to a piston rod. In itspreferred embodiment the core consists of a baked or dried sand bodyformed according to any suitable formula of sand or other material, andbinder adapted for the purpose. The core is preferably hollow, includinga body portion 10 of such diameter and length that when inserted in aprint, above deing space 9 between the core and the print, "and is alsoformed with meanswhereby the fillet 11 at the juncture of the, head andskirt of the piston casting (see Fig. 6). At a point intermediate itsends the body portion may be provided with diametrically oppositerecesses 12, which when the core is in position in the-print communicatewith the annular space in the print and receive the metal to provide thecasting with internal bosses 12 to receive a gudgeon pin for connectinathe finished piston to a piston rod.

At its upper end the core is formed with suitable means for closing theannular castcore may be supported by an end at a point external of theprint and the sand mold in the flask.

ential shoulder or flange 13 having a preferably horizontal under face14 extending laterally from the core and of such width radially thatwhen the core is in position in the mold print said face extends beyondthe edge of the print and cooperates with the mold to thereby close theannular space between the core and the print, and define the bottom edgeof the skirt of the piston casting. By the shoulder 13 the casting space9 is separated or insulated from the core-supporting means to behereinafter described, and chilling of the casting which might result inobjectionable internal strains, from contact with said means, isobviated. Thecore may be formed adjacent the face 14 with anannularrecess 14 to provide for an internal reenforce for the skirt of thepiston casting.

The said supporting means carried by or forming. part of the core,comprises a head 15, also integral with the core, beingforined of thesame composition material, and in its preferred form; is aslaterallyprojecting member 16, preferably circular and locate-d above projectingbeyond themold or printclosing shoulder 13. The center of the sup,-porting head 15 is coincident with the longitudinal axis of the core,and the projecting part thereof is made equidistant from said center atall points to facilitate adjustment, as will be hereinafter described.The periphcry of the member 16 is beveled downward andinward, as at 16.The core is preferably made hollow, and in its preferred embodiment isformed with an axial cavityf18 which opens at its top through the upperend of the core and terminates at its lower-end, preferazbly 1 at apoint below the. boss-formingre The said means for closing the annularspace preferably conslsts of a circumfer- I cesses- 12 heretoforedescribed; I provide for gating the mold,'preie-rably by forming one ormore pouring ports 19 cominunlcating with the said p0 ring cavityandopening through the wall of the core into the said recesses', so thatw ien the metal is poured into the cavity it flows through said portsintothe recesses and into the space in the print around the core.

I provide means its end portion or head, heretofore described, whichprojects above or beyond the mold .or flash, and for accuratelycentering and holdmetal linefor the skirt of the piston casting isassured. This means preferably consists of a rigid member in the form ofa plate 20 adapted to lie over and cover the top of the mold, and havingguide and positioning pins 2'1 accurately positioned thereon tocorrespond to the position of the pins 6 on the pattern board, and theguide '0 )enings 3 in the flask. This plate carriesmeans for sup portingone or more of said cores so as to center the latter accurately in theprint, and

forthis purpose said plate is provided with one or more apertures 22shaped to conform toor. match the periphery of the supporting head onthe core, saidapertures being preferably circular and of such diameterthat the wardly extending annularfiange QS-having horizontal supportingshoulder or face 24 upon which the supporting shoulder 17 on the corerests, and said flange is provided with a circular fac 2?, preferablyinclined inwardly anddownwardly to engage the correspondingly formedface 13 on the print-closing shoulder of the core. The-wall of theaperture above the shoulder is beveled inwards at 24 It will thus beseen that when the plate is applied to the mold with its apertures overthe print in the mold, a: core may be inserted through each saidaperture to locate the body of the core in the print, and

that when the core is so located the printclosing face 14 will pro ectlaterally over the edge of the mold in the flask; the'inclined.

face 13 will contact the inner annular face 25 in the aperture, and theface 17 of the shoulder 16 will rest upon the shoulder 24 in the wall ofthe aperture. The face 16 on the core will seat against the beveled face24 in the.

wall of the aperture. By accurately forming the inner wall of the plateaperture, the "shoulder 24 and the cooperating face 17 on the core,and'also theinclined faces on the core and v aperture,"the core wheninsertedinc for supporting the core by ing the core in the print so thata uniform position to be supported by the plate will be accuratelycentered within the print and thereby assure a uniform metal line forthe shirt and head. The cooperating inclined faces on the aperture andcore head cause the core to be automatically centered in the aper turand print.

In the preferred form means is provided for holding the cores in theposition just described to assure that they will not be dislod d, due topressures gen rated in the mold when the latter is poured. For thispurpose the upper end or head of the core is preferably made of suchvertical thickness as to provide a horizontal face 28 in a plane atright angles to the longitudinal axis of the core and located above theupper face of the core-supporting plate :20, and the cores are held downby suitable means, as a weighted member, preferably in the form of aplate 29 aoapted to rest upon the horizontal faces 28 when the cores arein place in the plate 20. This plate 29 is provided with pouringopenings 30 which are located overthe pouring cavities 18 in the cores.it will thus be seen that the cores are held from lateral movement inthe prints due to pressures generated in the print, and that the plate29 prevents longitudinal displacement of the cores from the prints. Itwill also be seen that the part 13 on the core which overhangs andcloses the upper end of the print separates the mold cavity andtherefore the molten metal therein, from access to and contact with anypart which might act as a chill for the lower edge portion of the skirtof the piston casting. lVhen the core is in position it merely contactsor rests lightly upon the edge of the mold and does not crush or breakdown the mold. This is accomplished by making the shoulder 13 of aproper thickness to effect the result stated. It will also be seen thatthe cores are supported by means which is external tothe mold in theflask, so that deformation of the mold print due to any cause, cannotdisturb the accurate position of the core in the print.

In carrying out the method, the supporting means consisting of theapertured plate 20 is adjusted over the open end of the mold and isaccurately positioned thereon relative to the print by means of thecooperating guir consisting of the pins 21 and apertures The cores arethen dropped into place and are automatically centered and held inproper position relative to the print or cavity, due to the formation ofthe cooperating faces on the cores and said supporting )lZIlIG. By m1..ing the apertures in the plate and the supporting part of the corescircular, the cores may be app ied without regard to a y particularcircumferential relation to the print, as they will be accuratelycentered no matter what angular position they bear while'being inserted.The holding member or weight 29 is then located over and upon the upperends of the cores, so that the latter are rigidly held on the supportingplate, whereupon the metal is poured through the apertures 30 in theholding plate into the cavities in the cores to form the casting (seeright-hand mold in Fig. 6). Bythe use of the memb 29 and the manner ofsupporting the core by the plate :20, the core is held against movementin both directions longitudinally of the print. lhe casting A is substtiaL-y cylindrical, including the head B and cylindrical skirt C open atthe end opposite to the head, and having the internal bosses 12heretofore mentioned. The sprue in the centralpouring cavity of the coreis indicated at D, Fig.6, and is connected to the bosses by tie metal inthe pouring ports or gates 19.

In order to assure the greatest accuracy and permit replacement in caseof wear, each of the apertures in the supporting plate may be lined withrings or liners 31 having theconfiguration above described for saidapertures, this provision permitting ready replacement in case saidliners become worn or defaced so as not to accurately center a core; butit will be understoodthat the supporting faces may be made eitherintegral with the plate 20 or bymeans of such liners just decribed.Theopenings 3 may also be lined, if desired, with replaceable bushings3.

By the above method and apparatus I am able tovcast a metallic pistonwith practically any desired uniform thickness of metal line, but theinvention is particularly useful-in casting pistons to a specifiedweight with a comparatively thin metal line, inasmuch as the accuratepositioning and holding of the cores enables, me to obtain a thin metalline which will be uniform at all points and-not greatly in excess ofthat of the finished product, so that a small amount of machining isnecessary. It will also be seen that the metal. line beinguniform, thepiston may be machined, as, for example, cutting the grooves for pistonrings to the proper depth without danger of cracking or cutting throughthin parts, which were liable to occur incident to the old methods.

It will also be seen that by casting the complete piston in the dragsection of a mold, the casting will be truly cylindrical, requiringlittle machining, and be free from ridges which result from partinglines in sand molds of the cope and drag type. or ridges due tonon-matching of molds of the cope and drag type, which it is diflicultto avoid.

The method and apparatus provides not only for casting of pistons whichwill be cylindrical, of uniform metal line, light in weight, and freefrom internal stresses, but

also provides, in the case of multiple casting,

uality of thecastingbut reducing the costdue to saving of metal, anddue'toilow losses;

head, whichwas'not possible in ililSiOlCl methods. where it was requiredto considerablyoverweight the casting'in order to as Lire sufficientmetal line to machine it to specincation. By providing a thinuniforinmetal line for the casting, it is possibleto machine the same toa thickness of or" an inch in the finished piston, the macl'iininglossbeing reduced from at least per cent. to an average loss of about oneper cent. 7

What I claim and desire to. secure by Letters Patent of the UnitedStates is:

1. A molding apparatus of the character described comprising a flaskbody containing a sand mold having a print to form the external contourof a complete substantially cylindrical piston, a sand core in saidprint and coaxialtherewith, said core having at one end a sand partcooperating with the sand mold to close the opening into the print, andalso having a circumferential laterally projecting supporting part atsaid end, said supporting part being vertically offset from said closingpart, and means sup ported by said body and positioned external to themold for engaging said supporting part to hold the core against lateraland longitudinal movement in the print.

2. A molding apparatus of the character described comprising a flaskbody containing a sand mold having a print to form the external contourof a complete substantially cylindrical piston, a supporting platemember overlying the mold and external thereto, said supporting memberbeing supported by said body and having an aperture therein over theprint, coacting means between said body and said supporting member formaintaining said aperture in a determined relation to the print, and acore in said print, said core and member having cooperating meanswhereby the core is supported in said aperture and maintained againstlateral movement in the print.

3. A molding apparatus of the character described comprising a flaskbody containing a sand mold having a print to form the ex ternal contourof a complete substantially cylindrical piston, a supporting plate member overlying the mold and being supported by the flask body and havinga shouldered am able to cast a piston aperture therein; means; betweenthe flask y-an t e uppr n i m or; in-, taining the apertureini thelatter in a deter;

mined 'r elation toQtheprint, and a. corezin d-"P n a xi l he e th anhav ng a part engaging said shouldered aperture-to support the weight ofsaidcore from said body to prevent injury to said sand mold and wherebythe core is held against movement in the print. p y

4. A molding apparatus of the character described comprising afiask bodycontaining a sand-mold having a, print to form the external contour of acomplete substantially cylindrical piston, a supporting plate mem{ beroverlying-themold and having a shouldered'apertureforguiding a core intoand centeringthe axistof. the core coincident with the axis of theprint, a core in said print and having apart external to the print andlocated in said shouldered aperture to hold thecore coaxial withtheprint,.a-nd meansfor engaging-said core part to-hold the same.

against longitudinal movement inthe print, o

said last-named means including a weighted member, engagmg the pro ect1ng endot the, core. 7

5.; A molding apparatus. ofthe character described comprisingaflasklbody containing a sand mold having a print to form the externalcontour not acomplete substantially cylindrical piston, supporting-means removably mounted on, said body and overlying said-moldandihaving ashouldered aperture therein to receiveand guide; core;intosaid-L print, core coaxial with said printan dehave ing. an-endportion extendingexternally of the print andhavingat its end external tothe, print asand part engagingsaid shouldered: aperture whereby the coreis held. against lateral movement ,inithe print and removably. supportedinthe'aperture, said core-having alongitudina-l pouring; cavity gatedthrough- U thesidegv all of thecoreinto the print, and means overlyingsaid supporting member and engaging the external vend of theycore tohold the latter against longitudinal movement in theprint,-:s,aid,last-named means having a pour-ing aperture; communicatingwith the cavitylinthe'corea 7 I V 6. A molding-apparatus of thecharacter described comprising a flask body containing asandmoldihavinga print to fOIll'LilllQ ex:- ternal contour of-a completesubstantially cylindrical piston, a supporting; platefmemberremovablymounted on said body and overlying: the mold and, externalthereto an d having; an aperture therein. over the print, coactingguidemeai isonsaidtbody and said; supporting member for positioning and,maintaining: said aperture in a determined relation to the print, a.core insaid print and; extending through theaperture in said member, andcoact-ing, faces: on the member and. core for. centering the core in theprint,-

Eli)

7. A method of casting pistons, which coinprises forming in a flask asand mold having a cylindrical print for the external form of a completecylindrical piston, positioning a core-supporting member on said flask,suspending a core from said member coaxial with said print, holding saidcore to prevent displacement thereof, and then pouring aid mold. a

8. A method of casting pistons, which compises forming in a flask a sandmold having a cylindrical print fof the external form of a completecylindrical piston, positioning on said flash a core-supporting memberhaving an aperture therethrough coaxial with said print, suspending acore through said aperture into said print, holding said core to preventdisplacement thereof, and then pouring said mold.

9. A met 10d of casting pistons, which comprises forming in a flask asand mold having a cylindrical print for the external form of a completecylindrical piston, fixing on said flask against horizontal movement acoresupporting member having an aperture therethrough coaxial withsaidprint, suspending a core from said member through said aperture intosaid print, weighting said core to prevent displacement thereof, andthen pouring the mold. r

10. .A. molding apparatusfor casting pistons, comprising a flask bodyhaving a substantially vertical surrounding side wall, guide meanspositioned oppositely and projecting from the external top portion ofsaid side wall, said flask bodycontaining molding sand having acylindrical mold print formed therein, a plate member supported by andon said side wall and having a circular aperture therethrough of adiameter greater than the diameter of said print, said plate memberbeing recessed about said aperture to provide an upward facing annularshoulder, means on said plate member c'ooperable with said guice meansto position said plate member on said body with said apertureconcentrically over said print, a sand core member in said aperture andremovably supported by said plate member, said core member having acircumferential flange of a diameter substantially equal to the diameterof said aperture whereby said flange closes the top end of the annularmetal receiving space and having a flange above and extending laterallyfrom said first-named flange, said second-named flange cooperating withsaid upwardly facing shoulder to support said core member.

11. A molding apparatus for casting pistons, comprising a flask bodyhaving a substantially vertical surrounding side wall, guide meanspositioned oppositely and projecting from the external top portion ofsaid side wall, said flask body containing molding sand having acylindrical mold print formed therein, a plate member supported by andon said side wall and having a circular aperture therethrough of adiameter greater than the diameter of said print, said plate memberbeing recessed about said aperture to provide an upward facing annularshoulder, means on said plate member cooperable with said guide means toposition said plate member on said body with said apertureconcentrically over said print, a sand core member in said aperture andremovably supported by said plate member, said core member having acircumferential flange of a diameter substantially equal to the diameterof said aperture whereby said flange closes the top end of the annularmetal receiving space and having a flange acting by force of gravity tohold said sec-,

end-named flange against said shoulder.

In testimony whereof I have hereunto signed my name.

i DANIEL H. MELOCHE.

